Airborne ultrasound echoes could be used to detect non-sounding people.
There are methods for detecting the surrounding information by analyzing ultrasound echoes [1]}, [2]}, [3]}, [4]}, [5]}, [6]}, [7]}.
Although these methods can estimate the position of objects, methods that specialize in human recognition and estimate human segmentation have not been well investigated.
If human segmentation can be estimated from echoes, it would be possible to detect non-sounding people and it can be used to estimate human action.
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